Monolithic ceramic capacitor with barium titinate dielectric curie point optimized for active implantable medical devices operating at 37 degrees centigrade
First Claim
1. A feedthrough filter capacitor assembly for use in an active implantable medical device, comprising:
- at least one conductive terminal pin;
a feedthrough filter capacitor having first and second sets of electrode plates disposed within a dielectric material having a dielectric constant greater than 7000, and a first passageway through which the terminal pin extends in conductive relation with the first set of electrode plates, wherein the feedthrough filter capacitor is optimized for operation within the range of 30°
C. to 40°
C.; and
a conductive ferrule through which the terminal pin passes in nonconductive relation.
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Accused Products
Abstract
A feedthrough filter capacitor assembly for use in active implantable medical devices and a related process for manufacturing a monolithic ceramic capacitor utilizing dielectric materials having a dielectric constant greater than 7000, and preferably in the range of 8500 to 22,000. In the manufacture of the monolithic ceramic capacitor, one or more Curie point shifters and/or other dopants are added to the dielectric material to optimize the dielectric constant at the human body temperature of 37° C. For manufacturing purposes, dopants may be added to the dielectric material to broaden the Curie point peak or point of maximum dielectric constant thereof. The effect is that when such capacitors and terminal assemblies are utilized in a high-voltage defibrillator circuit of an implantable medical device, the dielectric material is optimized so that during the delivery of high-voltage electrical energy, capacitance value of the capacitor drops substantially.
44 Citations
31 Claims
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1. A feedthrough filter capacitor assembly for use in an active implantable medical device, comprising:
-
at least one conductive terminal pin;
a feedthrough filter capacitor having first and second sets of electrode plates disposed within a dielectric material having a dielectric constant greater than 7000, and a first passageway through which the terminal pin extends in conductive relation with the first set of electrode plates, wherein the feedthrough filter capacitor is optimized for operation within the range of 30°
C. to 40°
C.; and
a conductive ferrule through which the terminal pin passes in nonconductive relation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A feedthrough filter capacitor assembly for use in active implantable medical devices, comprising:
- at least one conductive terminal pin;
a conductive ferrule through which the terminal then passes in nonconductive relation;
a feedthrough filter capacitor having first and second sets of electrode plates disposed within a dielectric material having a dielectric constant greater than 7000, and a first passageway through which the terminal pin extends in conductive relation with the first set of electrode plates, wherein the feedthrough filter capacitor is optimized for operation at 37°
C.; and
a ground lead which extends into a second passageway through the feedthrough filter capacitor, wherein the ground lead is conductively coupled to the second set of electrode plates and the conductive ferrule. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
- at least one conductive terminal pin;
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18. A process for manufacturing a monolithic chip capacitor for use in an active implantable medical device, comprising the steps of:
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providing a dielectric material having a dielectric constant greater than 7000;
adding one of more Curie point shifters to the dielectric material to optimize the monolithic chip capacitor dielectric constant at the human body temperature of 37°
C.; and
processing the dielectric material with the added shifters into a finished monolithic chip capacitor having first and second sets of electrode plates disposed therein. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25)
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26. A process for manufacturing a monolithic chip capacitor for use in an active implantable medical device, comprising the steps of:
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providing a dielectric material having a dielectric constant greater than 7000;
adding one or more Curie point shifters to the dielectric material to shift the point of maximum dielectric constant to 37 degrees C.;
adding a dopant to broaden the Curie point peak of the dielectric material;
optimizing the dielectric material so that during the delivery of high-voltage electrical energy, capacitance value of the monolithic chip capacitor drops to less than 65% of its initial value; and
processing the dielectric material with the added shifters and dopant into a finished monolithic chip capacitor having first and second sets of electrode plates disposed therein. - View Dependent Claims (27, 28, 29, 30, 31)
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Specification